ISC BIND 9.15.6 < 9.16.6 / 9.17.x < 9.17.4 DoS

#
# (C) Tenable Network Security, Inc.
#

include('compat.inc');

if (description)
{
  script_id(139921);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2021/06/03");

  script_cve_id("CVE-2020-8620");
  script_xref(name:"IAVA", value:"2020-A-0385-S");

  script_name(english:"ISC BIND 9.15.6 < 9.16.6 / 9.17.x < 9.17.4 DoS");

  script_set_attribute(attribute:"synopsis", value:
"The remote name server is affected by a denial of service vulnerability.");
  script_set_attribute(attribute:"description", value:
"According to its self-reported version number, the installation of ISC BIND running on the remote name server is 
version 9.15.6 prior to 9.16.6 or 9.17.x prior to 9.17.4. It is, therefore, affected by a denial of service (DoS) 
vulnerability due to an incorrectly specified maximum buffer size. An unauthenticated, remote attacker can exploit this
issue by sending a specially crafted large TCP payload to trigger an assertion failure, causing the server to exit.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version   
number.");
  script_set_attribute(attribute:"see_also", value:"https://kb.isc.org/docs/cve-2020-8620");
  script_set_attribute(attribute:"solution", value:
"Upgrade to BIND 9.16.6, 9.17.4 or later.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2020-8620");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"vuln_publication_date", value:"2020/08/20");
  script_set_attribute(attribute:"patch_publication_date", value:"2020/08/20");
  script_set_attribute(attribute:"plugin_publication_date", value:"2020/08/28");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:isc:bind");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"DNS");

  script_copyright(english:"This script is Copyright (C) 2020-2021 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("bind_version.nasl");
  script_require_keys("bind/version");

  exit(0);
}

include('vcf.inc');
include('vcf_extras.inc');

vcf::bind::initialize();

app_info = vcf::get_app_info(app:'BIND', port:53, kb_ver:'bind/version', service:TRUE, proto:'UDP');

constraints = [
  { 'min_version' : '9.15.6', 'fixed_version' : '9.16.0', 'fixed_display' : '9.16.6, 9.17.4 or later' },
  { 'min_version' : '9.16.0', 'fixed_version' : '9.16.6' },
  { 'min_version' : '9.17.0', 'fixed_version' : '9.17.4' }
];
constraints = vcf::bind::filter_constraints(constraints:constraints, version:app_info.version);

vcf::check_version_and_report(app_info:app_info, constraints:constraints, severity:SECURITY_WARNING);